Machine tools



April 1967 G. H. KENDALL, SR;. ETAL 3, ,778

' MACHINE TOOLS U Original Filed Sept. 18, 1956 lQ'Sheets-Shet 1 774;!

INVENTORS George H. Ker/d027, Jr! 1 Jerfly A. Host Robert E. Wa 'd BYGeorye HKendaZLJr:

ATTORNEY) April 275, 6 G; H. KENDALL, SR. ETAL. 3,315,778

MACHINE TOOLS Original Filed Sept. 18, 1956 10 Sheets-sheet. 2'

INVENT R5 George H. Ken 022,5: Jen/ y '9, Host: Robert E. Ward April 25,1967 G. H. KENDALL, sR.. ETAL. 3,315,778

MACHINE TOOLS Original Filed Sept. 18, 1956 l0 Sheets-Shee 5 INVENTORSGeorge H. KendaZZSr Jerry 14. Host Robert 5 Ward BY Geo/ye h. Kendall/l:

ATTORNJSXS' Ap i 25, 1967 G. H. KENDALL, sR.. ETAL.

MACHINE TOOLS l0 Sheets-Shee 4 Original Filed Sept. 18, 1956 Y u 4 mf2%, m W W a 9X? rr r 3% 5 2 Ap 1957 G H. KENDALL, SR, ETAL. 7

MACHINE TOOLS I Original Filed Sept. 18, 1956 l0 Sheets-Shee 5 18a 23 II 13a 7 e/ r Z4 Z5 IN VEN TORS Jerry H. /4257" Babel-f 5'. Ward 5y eoryeH Kendall, Jr:

fiTTOENEY-S iearye H Kendal/ Sr Apri 1967 G. H. KENDALL, sR.. ETAL.3,315,778

' MACHINE TOOLS Original Filed Sept. 18, 1956 l0 Sheets-Sheet 6ATTORNEYS MACHINE TOOLS Original Filed Sept. 18, 1956 l0 Sheets-Sheet 7INVENTORS George 16- Kendall .51: Jerry 9. H061- Babe/4' E. WardATTORNEYS April 25, 1967 G. H. KENDALL, 5R, ETAL 3,315,778

MACHINE TOOLS Original Fild Sept. 18, 1956 1o Sheets-Sheet 8 INVENTORS19 H. Kendall, Sn Jew/"y 9. Host obert E. Ward BY Geo/ye h. Kendall, Jr?

Ap 5, 1967 G. H. KENDALL, sR.. ETAL 3,315,778

MACHINE TOOLS v Original Filed Sept. 18, 1956 1o Sheets-Sheet 9INVENTORS Geo/ye H. Kendall, 5/: Q Jerry fl. H057 Eoberf 5. Ward, N 3yeorye H. Kendall, J/r

\ V ATTORNEYS p l 25, 1967 G. H. KVENDALL, SR. ETAL 3,315,778

MACHINE TOOLS Original Filed Sept. 18, 1956 10 Sheets-Sheet 10 1/6 jM/fiH I b 07 MKQL;

A TTORNEYJ United States Patent 3,315,778 MACHINE TOOLS George H.Kendall, Sn, Darien, Jerry A. Host, Fairtield, Robert E. Ward, Wilton,and George H. Kendall, J13, Groton, Conn, assignors to KenhosDevelopment Pool, Darien, Conn, a co-partnership Continuation ofabandoned application Ser. No. 186,316, Mar. 30, 1962, which is acontinuation of application Set. No. 610,446, Sept. 18, 1956. Thisapplication Nov. 25, 1964, Ser. No. 418,944

2 Claims. (Cl. 1198-19) This application is a continuation of ourapplication Ser. No. 186,816, filed March 30, 1962, now abandoned, whichis a continuation of our application Ser. No. 610,- 446, filed September18, 1956, now abandoned.

This invention relates to machine tools, and more particularly to amulti-station machine tool for performing operations sequentially on asuccession of workpieces passing through the machine.

An object of this invention is to provide a basic machine tool havingprovisions for mounting a large number of tool units of various kinds onworking position, builtin facilities for controlling the operation ofthe tool units, improved means for advancing workpieces progressivelyand intermittently to successive tool units, timing means forcoordinating the operations of the tool units and workpiece-advancingmeans, and manual and automatic means for controlling the length of timein which a complete cycle of operations is to be performed.

To accomplish this and other objects, the present invention involvesmany advantageous features, among the most important of which is theprovision of a machine having a frame provided with a worktable having aplurality of straight intersecting ways forming a closed track ofpolygonal form and substantially filling said track with rows ofindividual work carriers by which the work is advanced step-by-step tosuccessive work stations at which the tool units are mounted to receivethe operations required to be performed.

Preferably, alternate rows of carriers around the track are advanced atthe same time, after which the other rows are advanced simultaneously.When the machine is so arranged, the rows of carriers fill the stretchesof the track except that at alternate intersections around the track onecarrier is omitted to provide space to receive the first carrier in theadjacent row.

The track may form a rectangle or other polygonal outline and the workstations may be along any or all sides thereof. Advantageously, however,the track is so formed as to be oblong and the tool units are locatedalong the two long sides, thereby providing adequate space for and easyaccessibility to the many tool units some times required, the operationsbeing performed both in the long stretch of the track leaving thestarting point and the long stretch of the track returning to thestarting point.

Since the ways intersect angularly, the work carriers move from onestretch of the track to the next without changing their orientation inrelation to the machine as a whole. Therefore, according to the presentinvention, in each stretch of the track a difierent side of the carrierand workpiece thereon is presented to tool units along the perimeter ofthe several stretches of the track, thereby, in many cases, avoiding thenecessity of rotating the work carrier and/ or the work for thispurpose.

In those stretches of the track along which tools are located, the workcarriers are advanced step-by-step by power-operated reciprocatory meanswhich includes feed lugs to engage and disengage the carriersindividually, and after advancing them leaves them in slightly spacedrelation free for slight registering movements which are brought aboutby cooperating aligning means on the tool units and the work carriers.The work carriers in all stretches of the track may be advanced by thisform of reciprocatory mechanism, but in those stretches of the trackalong which there are no tool units the entire row of carriers may bemoved by a single reciprocating .advancing means engaging the lastcarrier in the row.

Another important feature of the invention is the provision of meanswhereby tool units may be mounted on the worktable of the machine withinthe outline of the track so that the tools may move outwardly to engagethe work or downwardly to engage the work; or the tool units may bemounted outside the outline of the track so that the tools may approachthe work from the outside or from the top of the machine.

In addition, the machine of the present invention is preferably soarranged that the tools may engage the work from the underside of thework carriers, and for this purpose and wherever this is to be done, thetrack is provided with a vertically open space which extends downwardlyto a shelf-like rail carried by the frame under the ways and the toolunits are mounted on the rail to be directed upwardly toward the workcarrier and the work thereon. When this provision is made, the sides ofthe machine are made so as to be open to give access to the shelf-likerail and tool units thereon for the mounting, inspection and adjustmentof tools.

The work carriers of the present invention may have any desired form orshape and may carry suitable jigs and fixtures for receiving and holdingthe work. Each work carrier is provided with guide surfaces for engagingthe ways and said guide surfaces are so formed as to permit the transferof the carriers from one section of the track to the adjacent section.The carriers may be held normally captive on the ways, in which case thework will be placed on the carrier at a work-loading station. However,in some cases, it is advantageous to have the carriers free of the waysso that they can be lifted off and applied to the ways without the useof tools, thus permitting a defective carrier to be removed at any placealong the track to be replaced by a satisfactory carrier. When thecarriers are removable either anywhere along the track or at somedesignated place, extra carriers may be provided whereby a workpiece maybe secured to a carrier in advance outside the machine to substitute fora finished workpiece and its carrier at a loading and unloading station.

Another feature of this invention is the provision of improved controlmeans for the tool units including tim ing mechanism for controlling thesequential operations of the tool units and the work carrier advancingmeans. Such control means preferably includes means for selectivelyvarying the length for one complete cycle of operations of the machine,and means for manually starting and stopping the operation of themachine, thereby permitting the same basic machine to be retooled forperforming other operations without the necessity of completelyreorganizing the control mechanism except possibly to change the lengthof time of a cycle.

Another feature of the present invention is the provision of automaticmeans whereby the advancement of the work carriers will be interruptedunless each step is completed properly, and also means for stopping theoperation of the machine in the event that, for some reason or other,the tool units have not returned to their starting position before thebeginning of the next cycle of operations. These safety means includemeans whereby the machine cannot be restarted without performing amanual operation.

It should be noted that the machine of the present invention may betooled for performing any operations which can be performedautomatically whether they are generally classed as machining,assembling, treating or other operations, and therefore that the termtool unit as used herein is intended to include any and all forms oftooling mechanisms operated automatically to perform intended functions.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

FIGURE 1 is a front elevation of the machine tool as it appears beforethe tool units are attached.

FIG. 2 is a plan view of the machine shown in FIG. 1 illustrating toolunits attached to the machine.

FIG. 3 is a plan view of a representative workpiece for which the palletnests as herein shown by way of example are formed.

FIG. 4 is a transverse section showing the construction of the frameworkof the machine, and showing the ways for the pallets as gibs.

FIG. 5 is a transverse section through the machine showingrepresentative tool units mounted in position above, outside and belowthe pallets and the workpieces thereon.

FIG. 6 is a fragmentary plan view showing one end of the machine, andparticularly showing the pallet-advancing mechanism-the parts beingshown in the positions which they occupy at the beginning of the cycleof operations.

FIG. 7 is a view partly in section showing a pallet, a workpiecesupported thereon, a hold-down device for the workpiece, and registeringpins for accurately positioning the pallet in the ways before the workis performed.

FIG. 8 is a fragmentary transverse sectional view of a portion of themachine showing a form of pallet and mounting therefor in which thepallet rides on rails, and showing troughs for collecting coolant,lubricant, chips, etc. resulting from operations of tooling units.

FIG. 9 is a plan view of a corner of the machine showing the parts shownin FIG. 8-the pallets being shown in the positions which they occupyafter one row of pallets has been advanced and before the other row ofpallets is advanced.

FIG. 10 is a perspective view of one end of the machine showing thepallet-advancing mechanism.

FIG. 11 is a transverse sectional view through one of the ways showingthe pallet-advancing rods with their feed lugs engaging the pallet, andshowing in dotted lines the position of the feed lugs disengaged, asduring the return movement of the feed rods.

FIG. 12 is a longitudinal section through the pallets showing the feedrods with the feed lugs engaging the pallets, and showing grooves forguiding coolant, chips, etc. to the collecting troughs.

FIG. 13 shows one end of the machine with some of the parts broken awayand other parts shown in section.

FIG. 14 is a view similar to FIG. 13, but showing the other end of themachine.

FIG. 15 is a diagrammatic view showing the hydraulic system foroperating the pallet-advancing means and indicating diagrammatically thepositions of the switches for controlling the solenoid valves which inturn control the cylinders and pistons for operating parts of thepalletadvancing mechanism.

FIG. 16 is an electrical diagram showing the various switches, relaysand other electrical units incorporated in the machine.

FIG. 17 is a vertical section showing the safety switch cable and itsmounting means.

FIG. 18 is a front elevation like FIG. 1, but showing an overheadarrangement for the conduit and plug receptacles forming part of theelectrical system.

The machine of this invention comprises a frame 1t? which has endsections 11 and intermediate sections 12 of such length, and as many, asmay be required to supply the desired working space. The frame 10 has atop or deck 13 and a vertical supporting structure 14 forming a baseadapted to rest on the floor or other foundation.

As shown in FIG. 2, the deck 13 is provided with straight ways 15 on itslong sides angularly intersecting straight ways 16 on its shorter sides.The ways form an oblong rectangular track 17 on which work carriers orpallets 18 may travel, and along which tool units T may be operated onor in connection with workpieces carried by the pallets 18. The ways 15and 15, as shown in FIGS. 2, 4, 6, 7, 10 and 11, may be in the form ofgibs and comprise bottom rails 19 having spacers 2t and top flanges 21.The pallets 18 are preferably rectangular, usually square, and havetheir lateral edge portions 22 confined between the rails 19 and flanges21 with the spacers 2i engaging the edges of the pallets to limit thelateral movement thereof.

When it is desired to provide for the removal and replacement of thepallets on the track, the flanges 21 or parts of them may be omitted.For instance, when it is desired to attach the workpieces to the palletsoutside the machine, the flange 21 may be omitted at a loading andunloading station along the track to permit the pallets with finishedWork to be lifted from the track and other pallets to which unfinishedwork is attached to be placed in position on the track.

When the machine is to be tooled to perform operations involving the useof lubricants or coolants or machining operations involving theproductions of chips or shavings, it is preferred to employ thearrangement shown in FIGS. 5, 8 and 9, wherein the pallets 13a areprovided on their undersides with grooves 23 inwardly spaced from theirlateral edges 22 to receive and ride upon vertical rails 24 forming thetrack 17. In this way, any extraneous matter, such as chips, etc., isprevented from lodging between the rails and the pallets. Besides,liquids such as lubricants or coolants may flow over the edges 22 of thepallets to be conveniently collected and disposed of.

As shown in FIGS. 8 and 9, the collection of the liquids used and chipsmade in the performance of operations of the machine is accomplished byproviding troughs or channels 25 in the worktable 13 of the machineparallel with and adjacent the track 17 or portions thereof. Thus,liquid flowing off the pallets or chips falling therefrom will fall intothe troughs 25 and be collected by conduits 26 leading to a suitablereceiver and separator, not shown.

To further avoid the depositing of chips etc. on the rails I 24 and tocontrol liquids which may be deposited on and how off the pallets, thelatter may be provided along their leading and/ or trailing lateraledges with flanges to substantially reduce any space existing betweenthe adjacent pallets in a row. As shown in FIG. 12, this may beaccomplished by providing on two opposite edges of the pallets 13,flanges 27 which substantially bridge the space between leading andtrailing edges of adjacent pallets leaving only sufficient space topermit relative registering movements of the pallets for purposesexplained below. The flanges 27 may have parallel grooves 27a inclineddownwardly and away from the center of the pallet to cause liquids toflow toward the troughs 25 rather than over the edges of the flanges 27.

According to the present invention, there are enough pallets 18 on theways 15 and 16 to completely fill the rectangular track 17 (except forcertain intersections of the ways) so that there are continuous rows 15aand 16a of pallets in the ways 15 and 16 respectively to be advancedalong the track.

Various means for advancing the rows of pallets stepby-step on theseveral ways may be employed. However, to reduce the time during whichthe advancing movements take place, it is advantageous to advanceopposite rows of pallets simultaneously and alternately with the otherrows. When the track is oblong, as shown in FIG. 2, and the pallets areto be advance-d counterclockwise, at one position of rest betweenworking cycles of the tools the pallets are omitted at the diagonallyopposite corners 28 of the track. The rows 15a of pallets are firstadvanced simultaneously so that the leading pallets move into alignmentwith the rows 16a. This operation causes spaces to be left behind thetrailing pallets in the rows 15a. Then the rows 16a are advancedsimultaneously to move the leading pallet in the row 15a and completethe step-by-step movement of all the pallets.

Suitable reciprocatory means may be employed for advancing the rows ofpallets 15a and 16a alternately, but it is preferable to have each rowof pallets advanced by its own individual mechanism, and as shownherein, the means for advancing the pallets on the ways 15 are alike andthe means for advancing the pallets on the ways 16 are alike.

Referring to the rows 15a, as shown in FIGS. 6, and 11, parallel withand located in a space below each pair of rails is a pair of rigid feedrods 29 mounted on rollers 30 carried by the frame of the machine. Therods 29 extend at one end through guide plates 2% beyond the track 17into the adjacent end section 11. The rods 29 are connected by acrossbar 31 which in turn is connected to an operating rod 32.

The feed rods 29 may be operated by any suitable means such asmechanical means in the form of a cam and follower, or electrical meansin the form of a field and armature, or hydraulic means such as a pistonand cylinder.

For punposes of illustration, the rod 32 as shown herein is secured tothe end of a piston located in a cylinder 33 to be operated by asuitable source of fluid under pressure by which the rods 32 areadvanced longitudinally a predetermined distance and returned. Each ofthe rods 29 is provided with a plurality of spaced feed lugs 34 whichextend up into the space between adjacent pallets 18. When the lugs 34are so positioned and the rods 29 are advanced, the entire row ofpallets a in the ways 15 will be advanced simultaneously, but eachpallet is advanced individually in spaced relation with adjacentpallets.

The longitudinal spacing between the lugs 34 on each rod is preferablyequal to the length of a pallet plus the space to be left betweenpallets, and the stroke of the piston rod 32 and the feed rods 29 issubstantially equal to the longitudinal spacing between the lugs 34-theforward movement of the feed rods 29 being limited by the engagement ofthe foremost pallet in the row 15a with the ways 16 and the returnmovement of the feed rods being limited by a stop 35 on the frame of themachine. The reciprocating movements of the piston rod 32 are controlledby switches referred to below.

In addition to moving longitudinally, each feed rod 29 is rotated,having a rotatable bearing in the crossbar 31 and guide plate 29a, sothat the lugs 34 may move out of engagement with the pallets to theposition shown in dotted lines in FIG. 11 before the return strokes ofthe piston rod 32 and feed rods 29 take place. For the purpose ofrotating the rods 29, the latter are provided with gears 36 and 37 to beengaged by teeth 38 and 39 respectively on opposite sides of a gear rack40 which in turn is connected to a piston rod 41 of a cylinder 42.Instead of being connected to a piston rod 41 and a cylinder 42, thegear rack 43 may be operated mechanically or electrically operated ifdesired.

When the piston rod 41 moves to the left as viewed in FIG. 10, the gear36 and its rod 29 and lugs 34 are rotated counterclockwise and at thesame time the gear 37 and its rod 29 and lugs 34 are rotated clockwise,thus moving the lugs 34 downwardly and toward each other to disengagethe pallets 18. When the lugs 34 have been released from the pallets,the rods 29 may be moved to the left to the position shown in FIG. 10,leaving the pallets in the row 15a in the positions to which they havebeen advanced.

After the rods 29 are returned to starting position, the rack bar 40 isautomatically operated to rotate the rods into pallet-engaging positionas will be explained below.

To facilitate the entrance of the lugs 34- in the spaces between thepallets the lugs may as shown in FIGS. 10 and .11 be beveled off to forma wedging surface on their sides which approach the pallets.

After the lugs 34 have disengaged the pallets, aligning means, describedbelow in connection with the tool units, position and hold the palletsat the Work stations and such positioning is provided for by spaces 43between the pallets in the rows 15a provided by the previous presence ofthe lugs 34 between adjacent pallets and by the loose fit between thepallets and the ways.

It should be noted that the provision by the present invention of therigid feed rods 29 with their fixed and spaced feed lugs 34 assures thecontinued proper positioning of the pallets and the work carried therebywith relation to the tools units T to which the work is brought, andthat there is no opportunity for the spacing between the feed lugs to bechanged or the length of the advancing movement to vary which is liableto occur with other forms of feed mechanisms.

If critical alignment beween the pallets and work carried thereby andtool units in the rows 16a is required, the advancing mechanism justdescribed in connection with the rows 15a may be duplicated for the rows160.

However, in the machine as illustrated herein it is not intended thatwork requiring critical alignment with tool units be performed in theways 16, and therefore it is not necessary to individually advance andcontrol the pallets in the rows 16a. Accordingly as shown the pallets inthe rows 16a may be advanced step-by-step by each pallet pushing thenext. This may be accomplished for each row 16a by means of a lug 44mounted on a :piston rod 45 of a hydraulic cylinder 46 which is sopositioned as to engage the last or end pallet 18 in the row 16a asshown in FIG. 10 in dotted lines and advance the entire row 16a ofpallets when fluid pressure is applied in the cylinder 46. The lug 44and piston rod 45 may be supported in any suitable manner, but as shownthe lug 44 is provided with rollers 44a riding on a plate 44b secured tothe frame of the machine.

The advancement of the rows 16:: causes the leading pallets therein tobe moved into the rows 15a ahead of the first pairs of lugs 34 to beengagedand advanced thereby when the rods 2% are again operated.

Since the pallet-advancing mechanism shown includes cylinders andpistons, the present invention provides valve mechanism for operatingthe pistons and controlling their direction of movement.

Accordingly, as shown in FIG. 14 (see also FIG. 15 there is provided adouble-acting valve 47 connected by pipes 43 and 49 to the cylinders 33,another double-acting valve 50 connected by pipes 51 and 52 to thecylinders 42, and still another double-acting valve 53 connected bypipes 54; and 55 to the cylinders 46. The valves 47, 50 and 53 areconnected by pipes 56 and 57 to a pump 58 and a sump 59 respectively.The valves 47, 50 and 53 may be operated by any suitable power,electrical, mechanical or hydraulic, but it is preferable for simplicityand economy to operate them electrically, and they are, therefore shownas solenoid operated valves. Each of the valves 47, 5t) and 53 is atwo-position valve applying fluid under pressure to opposite sides ofits associated pistons in its opposite positions.

As will be more fully explained below, the advancing movement of thepallets is initiated by timing mechanism incorporated in the machine andarranged to be effective after the lapse of snflicient time forcompletion of all the particular tool operations to be performed.

In the form of the invention shown, the timing mechanism starts themovement of the feed rods 29 in palletadvancing direction and thereafterthe successive operations are performed sequentially and independentlyuntil the advancement of all of the pallets is completed.

As will appear below, certain interlocks or sensing devices are providedby the present invention to stop the operation of the machine in theevent of malfunctioning of any of the sequential operations or thefailure of the tool operations to be completed as intended within apredetermined time interval.

The timing mechanism shown comprises a variable speed motor 6% mountedin one of the end sections 11. The motor 69 is geared to a shaft 61 onwhich there is mounted a disk 62 for controlling contacts 63 and 64which, when closed at a predetermined period in the cycle of operationsof the shaft 61, causes the solenoid valve 47 to move to position toapply fluid under pressure through the pipes 48 to the cylinders 33 andadvance the rows of pallets a. When the leading pallets in the rows 15areach their limit of movement properly aligned with the ways 16, thepiston rods 32 (see FIG. 6) engage and close switches 65 atdiametrically opposite corners of the track 17. The closing of bothswitches 65 (which are in series) energizes the solenoid valve 50 toapply fiuid pressure to the cylinders 42 through pipes 52 to cause therack bars to operate to swing the feed lugs 34 down and away from thepallets.

At the same time the switches 65 cause a circuit leading to the solenoidvalve 53 to be closed to apply fluid pressure to the cylinder 46 throughthe pipes 55 to operate the fecd rods 45 to advance the pallets in theways 6.6a.

When the feed rods 29 have completed their rotation to swing the lugs 34clear of the pallets, the rack bars 46 engage switches 66 to close acircuit leading to the solenoid valve 47 to cause iiuid under pressureto flow through pi es 4% and cause the cylinder to return the feed rods29 to starting position.

Upon the feed rods 29 reaching starting positions, switches 67 operatedby the piston rods 32 close a circuit to the solenoid valve 50 connectedby pipes 51 to cylinders 4,2 which operate the rack bars 4% to rotatethe feed rods 29 and position the lugs 34 between the pallets in therows 15a.

The feed rods 45 for the cross feed of the pallets are immediatelyautomatically and independently returned by the engagement of rods 45with switches 63 leading to the solenoid valve 53 connected by the pipes54 to the cylinder 46 for moving the lugs 44 to starting position.

Upon return of the feed rods 45 to normal position switches 68a areclosed and the return of the rack bar 4% to normal position closesswitches 66a.

Referring to the form of ways shown in FlGS. 4, 6 and 10 in which thepallets are confined to the track by flanges 21 to avoid malfunctioningof the machine or breaking of the parts in the event of some manualdisturbing of the pallets or some other reason the lugs 34- cannot enterthe spaces between the pallets, the rack bar may be connected to thepiston rod 41 by a yielding telescopic connection shown in FlGS. 6 and10, in which a spring 69 is placed between the rack bar 46 and thepiston 41. The relative movement between these parts is controlled by apin-and-slot connection 70. Should the lugs 34 be prevented from movingupwardly to proper position and the rack bar 49 be thus prevented frommoving, the continued movement of the piston rod 41 will cause theoperation of a switch 71 in a circuit which will stop the operation ofthe entire machine. The switch 71 is carried by a block secured to thepiston rod 41 and is operated by an arm 72 carried by a rack bar.

When the pallets, such as the pallet 18a shown in FIGS. 8 and 9, merelyrest on the rails and are not confined thereto, the pin-and-slotconnection "it? between the rack and piston may be omitted along withthe switch 71, since, if the lugs 34 do not properly align with thespaces between pallets, they will merely raise the pallet off the railsslightly. The next advancing operation will jog the pallet back intoposition on the lugs.

The tool units T may be made to operate at the completion of theadvancement of all the pallets. However, to reduce the time required forone complete cycle of the operations of the machine, it is preferable tostart the operation of the tool units as soon as the pallets in the rows15a have been advanced. Therefore, as shown herein, the switches 65which are operated by the rods 29 in the rows 15a when they completetheir advancing movements close a circuit referred to below which startsthe operation of the tool units.

The tool units T may, according to this invention, be mounted on theframe It anywhere along the tracts 17, if desired, to operate upon theworkpieces carried by the pallets 1% or assemble components of anarticle thereon. However, when, as shown in FIGS. 1 and 2, the machineis oblong, it is preferable and advantageous to mount the tool units Tonly along the long ways 15a, since sufiicient space for the tool unitsis usually available and they can be easily reached by a mechanic fromboth long sides of the machine for installation, adjustment andinspection. Such an arrangement is shown in FIG. 2, in whichrepresentative tool units T are placed in proper order to performmachining operations on workpieces carried by the pallets 13 as they arebrought successively to the positions of the tool units, i.e. to workstations.

The tool units T may be of any suitable or required kind depending onthe work to be done and, according to the present invention, may beconveniently mounted on the frame of the machine in any desired positionrelative to the outline of the pallet track 17. The tool units may bemounted on the deck 13 inside the track 17 as, for instance, themultiple drilling unit T1 shown in FIG. 5 which is mounted on a bracket74 bolted to the deck 13 and operates downwardly on the workpieces.

The tool units T may also be mounted on the frame to be located outsidethe track 17 as shown in FIG. 5, wherein the horizontal tapping unit T2is supported by a bracket 7: secured to the deck 13 and a brace 76secured to the side rail 77 at the lower portion of the frame of themachine.

in addition, according to the present invention, the tool units may belocated below the track 17 to operate upwardly on the workpieces carriedby the pallets. For this purpose, the frame of the machine is providedwith a deep open space or channel 78 directly under the pallets. At thebottom of the channel 7 8 there is provided a horizontal longitudinallyextending shelf 79, see FIG. 5, on which tooling units such as theboring tool T3 may be mounted to approach the workpiece carried by thepallet from the bottom and operate upwardly on the same. To provide aclear space in the channel 78 for such tool units, the feed rods 2? are,as shown, located close to the rails forming the track 17.

In order to give free access to the channel 78 for the installation,adjustment and inspection of tool units mounted on the shelf 79, theside members so of the frame on the long sides thereof have openings 81shown in FIGS. 1 and 5.

Tool units T may also be mounted on the deck 13 to operate horizontallyon the workpieces and approach the latter from the inside of the track17 or downwardly.

Since the pallets do not change the position at the corners of the tracktravel without changing their orientation with reference to the machineas a whole, the side of a pallet and workpiece facing the inside of thetrack in one of the ways 15a will be facing the outside of the track inthe other of the ways 15a, and thus either side of the workpiece may bereached by tooling from either the inside or the outside of the track.

The tool units T may be of any suitable type and may be operated in anydesired manner. As representative of the type of tool units well suitedfor use with the machine of the present invention, the tool units T1, T2and T3 shown in FIG. 5 are of the self-propelled, selfpowered typecomprising an electric motor 82 which supplies the power to rotate orotherwise drive the tool bit, tap or the like, and also to advance andretract a carriage S3 for the same.

The tool units T may also include testing and checking tools, such, forinstance, as the tool units T4 shown in FIG. 2, the details of whichform no part of the present invention.

The pallets 18 may have means to receive, locate and/or clamp aworkpiece on itself in the case of the machine being used for machiningoperations, or suitable holders or receivers for component parts in thecase of the machine being used for assembling operations.

Usually, because of the special provisions made by the presentinvention, it is suflicient in a case of machining operations to provideeach pallet with a work-holding nest 84, such, for instance, as shown inFIGS. 6, 7 and 10, which is shaped to fit a workpiece W, such as shownin FIG. 3, to be machined. Since in the present instance the workpiece Whas performed pilot holes W1, the nests 84 are provided with locatingpins 85 to be received by the pilot holes W1 in the workpiece.

When, as in the present instance, work is to be performed by tools suchas the tool unit T3 operating from the underside of the workpiece, eachnest 84- is provided tool. The pins 85 on the nests 84 not only locatethe workpiece relative to the pallet, but may also prevent the workpiecefrom rotating in the nest.

It should be understood, of course, that the work nests 84 will beformed differently for different shaped workpieces according to knownpractices in making jigs and fixtures.

To avoid the necessity of clamping each workpiece in its nest againstupward movement therefrom, there is associated with or formed as part ofeach tool unit T a hold-down device 87 which engages the workpiece atthe work station and holds it against being lifted out of the nest. Asshown in FIG. 5, a suitable hold-down device 87 may comprise aspring-pressed pad having one or more projections 88 so positioned as toengage the workpiece in the nest before the tool engages the workpieceand to remain in engagement with the work until the tool has beenretracted. The hold-down pad may, as shown in connection with the toolunit T 1 of FIG. 5, be mounted on the carriage 83 for the tools.

In the case of tooling units in which tools do not approach theworkpiece from above, a separate hold-down tool unit, such as the toolunit T shown in FIG. 7, may be employed. As shown in FIG. 7, thehold-down unit includes a hydraulic operator 89 connected to a slidableplate 90 which carries on its underside the hold-down pins 88 positonedto engage the flange W2 of the workpiece W for instance, when the plate90 is moved to operative position. Such hold-down units as the unit T5are conveniently mounted on the deck 13 inside the track 17 as shown inFIG. 2, and are used with such tooling units as units T2 and T3 shown inFIG. 5, but the illustration thereof in FIG. 5 is omitted for the sakeof clarity.

Associated with each tool unit T are aligning means for moving thepallets carrying a workpiece to be operated upon by that tool unit intoaccurate registration with with a central hole 86 to give access to thework by the the tools thereof. These aligning means are preferablycarried by the hold-down pads 87 as shown in FIG. 5, or the hold-downunit T5 as shown in FIG. 7 to which reference should be had. Theycomprise tapered pins 91 which, as shown, enter tapered holes 92 inbushings 03 mounted in the pallet and accurately located with referenceto the work nests 84. When the tapered pins 91 enter the tapered holes92, the pins will move the pallets if necessary to proper position andhold them thus until the tapered pins are withdrawn. This aligning andregistering movement of the pallet is permitted because by the time thatthe tapered pins 91 engage the tapered holes 92, the feed lugs 34located between the pallets have been withdrawn and the pallets arefree-to shift in the direction of feed. The pallets also have slightfreedom of transverse movement, since the grooves 23 in the pallets 18aare slightly wider than the rails 24 and the width of the pallets 18 isslightly less than the space between the spacer 20 in the form shown inFIG. 11.

The aligning pins 91 are so located that they engage the tapered holes92 in the pallets before the holddown pins engage the workpiece and alsobefore the tools are in position to operate upon the workpieces.

As shown in FIGS. 6, 13 and '14, the intermediate sections 12 which areadjacent the end sections 11 have frame sections 94 secured thereto bybolts 95. The-sections 94 support the outer rails of the sections 16 ofthe track 17 and the cylinders and other parts of the palletadvancingmeans and the controlling means therefor. Thus, the track 17 may beassembled on the intermediate sections without regard to the endsections 11 which thereafter may be put in position and secured to theintermediate sections.

The frame 10, as shown in FIGS. 1, 4, 5, 13 and 14, in addition to thetop plate 13, comprises side plates 96 and cross plates 97 which restupon and are secured to base units 98 adapted to rest on the floor orother suitable foundation. The base units shown in FIG. 13 are ofgenerally I-beam construction and have reinforcing ribs 99. Extendingacross the machine and secured to the base units are the side plates $50which extend up to the level of the table 13 and there serve as thesupport for the outer rails of the sections 15 of the track. The baseunits 03 extend beyond the sides 96 of the table and it is on theseextending portions of the base 95 that the shelf 79 is secured. Asstated above, the side plates have openings 31 giving access to thespace under the sections 15 of the track. Also, the sides have openings100 to give access to the space under the worktable 13.

The present invention makes provision for the convenient connection ofthe tool units T to operating and controlling circuits and to a sourceof compressed air. As shown in FIGS. 2, 4 and 5, the top plate 13forming part of the worktable is provided with a longitudinallyextending channel portion 101 midway between the long sides of themachine. Within the channel 101 there is located below the surface ofthe top plate 13 a conduit 102 for the wires and cables leading from theterminal board 103 in the end section 11 of the machine. tervals alongthe conduit 102 there are multiple wire receptacles 104 adapted toreceive attachment plugs 105 connected to cables 1% leading to the toolunits, as shown in FIG. 5 in connection with the tool unit T1 asrepresentative of the arrangement. The plug receptacles 104 arepreferably uniformly spaced along the conduit 102 without regard to thelocation of the particular tool units employed, since the cables 106 mayhave the necessary length to reach the tool units from the mostconvenient receptacle. The coded wires from each receptacle 104 passthrough the conduit where they are connected to terminals 107 at theterminal board 103 further referred to below.

To supply compressed air or other fluid conveniently to the tool units,the machine of the present invention is provided with a large pipe 108which extends longitudinally for approximately the full length of theframe between the ends 11. The pipe 108 preferably serves not only as aconduit and manifold, but also as a reservoir for the fluid. The pipe108 is preferably located below the channel member 101 and has connectedto it pipes 109 extending through holes in the channel and terminatingin coupling members 110 located in the channel to receive companioncoupling members 111 on flexible pipes 112 leading to the tool units orto the vicinity thereof as shown in FIG. 5. The pipe 108 also hascoupling members 113 attached directly thereto and ac cessible throughopenings 81 and 100 in the side plates 80 and 96 respectively to receivecompanion coupling members connected to flexible pipes leading to toolunits located below or outside of the track 17.

The present invention provides a simple and eflicient arrangement forcontrolling and interlocking the circuits At in- 11 leading to thepallet-advancing means and the tool units whereby successive operationsare started and completed in sequence and in timed relation; and if not,the operations are automatically stopped and cannot be restarted untilthe fault has been cured and a restarting switch operated.

This is accomplished by the use of switches and relays which will bedescribed in connection with the wiring diagram, FIG. 16, in which theswitch 114 is operated to connect a three-phase high voltage line 115 toa threew-ire system 116 in the machine. Across two of the wires 116there is a transformer 117 for supplying lower voltage current to therelays, solenoid valves and tool units. Current from one side of thetransformer 117 flows through a common lead return wire 118 whilecurrent from the other side of the transformer, after passing through afuse 119, flows to common leads 120 and 121. The lead 12% is connectedby a stop-and-start switch 122 through a lead 123, overload switches 124to a relay 125 connected to the return lead 118 to energize the relay.When the relay 125 is energized, a switch 126 closes the three-wirecircuit 116 to a motor 127 which operates the pump P to produce thehydraulic pres sure required to operate parts of the machine. At thesame time, switch 126a closes a holding circuit 128 which keeps therelay 125 energized until the stop button of the switch 122 is operated.

When the transformer 117 is energized, current therefrom is fed to avariable speed motor 619 for the timing mechanism. However, the motor611 does not start until another manual operation is performed.

Closing of the switch 126a causes current to flow to a start-and-stopswitch 130 which when operated closes a circuit including safetyswitches 131 and 132, wires 133 and a normally closed switch 134 of arelay 135 to a main relay 136 to energize the same.

Relay 136 closes a switch 137 in a holding circuit 138 around the startbutton of the switch 1311. The relay 136 also closes switches 139 and149 connected by wires 141 and 142 to the timing motor 611. The relay136 also closes a switch 143 which connects the common leads 121 and 121to feed current to the other units of the system.

When these operations have been performed, if the machine is in propercondition to start operating, i.e., the tool units are in startingposition and the automatic switches 66a, 67 and 68a are closed, theoperation of the timing motor 60 will cause the switch 63 to close. Whenthis occurs, current flows from the feed line 121 through switches 66a,67 and 68a, wire 144, switch 145 referred to below, wires 146 throughswitch 63, wires 14-7 through a normally closed switch 1% of a relay 149to a relay 150 to energize the same and cause a switch 151 to be closed.This causes current to flow from the feed line 121 through wire 152 tothe solenoid coil 47a which causes the pallets in the rows 15a to beadvanced, and when the advancement is completed switches 65 are closedto initiate the operation of the tool units and complete the next stepin the advancing of the pallets.

Closing of the switches 65 causes current to flow from the feed line 121through the wires 153 and 154- to the relay 149 to energize the same andthis causes the switch 148 to open and relay 1511 to drop out openingthe circuit to the coil 47a of the solenoid valve 47. At the same time,relay 149 closes a switch 155 connected to the feed line 121 by wires156 and 158 to a terminal 159 leading to the tool units to initiatetheir operations. At the same time, relay 149 closes a switch 160 of aholding circuit including wires 161 through a switch 162 of a relay 163and switch 64 of the timing mechanism so that the tool control circuitwill remain effective until the lapse of a predetermined time.

When the switches 65 are operated at the end of the advancement of thepallets in the row 15a, they also close a circuit including wire 164 anda closed switch 165 of a relay 16. The switch 165 connects to coil 50aof the solenoid valve 50 which causes the feed lugs 34 to be swung downclear of the pallets. When the lugs are clear, switches 66 are closedand they close a circuit including the wires 167 leading to the relay166 whose operation opens the switch 165 and deenergizes coil 50a of thesolenoid valve 51). Also, the switches 66 energize the coil 47b of thesolenoid valve 47 to return the feed rods 29 to starting position.

Return of rods 29 closes switches 67 to energize coil 56b through wire169 which causes the lugs 34 to be moved to operative position.

The switches 66 which are closed when the lugs 34 are clear of thepallets also closes a circuit including Wire 1711, switches 68 and wire172 leading to the coil 53 of the solenoid valve 53 which cause thepiston rods 45 and lugs 44 to advance the pallets in the rows 16a. Whenthis movement is completed, the circuit through wire 170 and coil 53a isopened by switches 68 and another circuit through switches 68, wire 173and coil 53b is closed to immediately and automatically return the feedlugs 34 to starting position.

At this point in the cycle of operations, all the switches 66a, 67 and68a have been closed. However, the reclosing of the switch 67, whichcontrols the advancing movement of the pallets in the row 15a, does notrepeat the cycle of the feeding operations because in the meantimesolenoid 150 has dropped out and the holding circuit, including theswitch 166 and the timing contact 64, remain closed, and this conditionis maintained until the end of the predetermined time controlled by thetiming motor.

The present invention makes provision for automatically rendering themachine inoperative under two conditionsone, in the event that thefeeding operation of the pallets for some reason takes too long, and theother if for some reason the tool units do not operate as intended andin the time required.

Referring now to the means for rendering the machine inoperative in theevent the transfer mechanism fails to operate properly, the presentinvention prouides a time delay relay 174 which is energizedsimultaneously with the coil 47a which causes the advancing movement ofthe feed rods 29 to position the pallets and the work thereon properlywith regard to the tool units T. The ener gization of the relay 174causes the closing of a switch 1'75 connected by wires 176 to relay 135which, upon energization, opens the holding circuit 134 and permits themain relay 136' to drop out and open all of the circuits. At the sametime the relay 135 closes a switch 177 in a holding circuit includingwires 17% leading back to the stop button of the stop-and-start switchAs a consequence, once the circuits controlled by the feed line 121 havebeen opened by the main relay 136, they remain open until a manualoperation has been performedthis being the operation of the stop buttonof the stop-and-start switch 130. At the same time, a lamp 179 incircuit with the relay 13-5 is energized to indicate a faulty condition.

As will be pointed out below, the tool units T may be provided withsensing switches which are operated when the tools have been returned totheir proper positions at the end of a tooling operation, and theseswitches are connected by wires in the receptacles 164 which in turn areconnected to the panel boardthe receptacle 104 being diagrammaticallyindicated in FIG. 16.

The wire 181) from the receptacle 164 is connected to the sensingswitches on the tooling, and unless current is flowing through the wire186/ to the relay 146 the latter will not be energized, and the switch145 which has been described above as a normally closed switch will notbe closed and a switch 181 will be closed. The closing of the switch 181sets up a condition through wires 167 which lead to the relay so thatwhen the switch 63 operated by the timing mechanism is closed toinitiate a new cycle of operations, the relay 135 will be energized andcause switch 134 to open, rendering the main relay 1-36 ineffective aspointed out above in connection with the other fault-sensing system. Atthe same time, the fault-indicating lamp 179 is energized. It will beunderstood, of course, that all of the sensing switches on the toolunits are in series so that if any one of them is not closed at the endof the tooling operation, the circuit leading through the wire 180 andrelay 146 will remain open.

In the operation of a machine tool involving transfer mechanism andmultiple tool units, it is advantageous in adjusting the tools and thepallet-advancing mechanism to inch or jog the mechanism so that thesuccessive operations can be observed conveniently.

For the pun-pose of permitting this to be done, the present inventionprovides the switch 145 which is a manually operated switch and whichhas three positionsan oif position indicated at 182, an automaticposition indicated at 183, and a manual position indicated at 184. Whenthe switch 145 is shifted to its manual operating position 184, the feedline 121 is connected by a wire 185 to the relay 163 which operates theswitch 162 to open the timer circuit controlled by the switch 64 of thetiming mechanism. At the same time, the wire 144 is connected by theswitch .145 to a wire 186 leading to a jogging switch 187 which, whenmanually held closed, connects the wire 144 through wire 186 to a wire.188 and wire 145 leading to the switch 63 of the timing mechanism. Theswitch 63, it will be recalled, starts the operation of the mechanism,hence the jog button 187 will substitute for the start timing switch 63.When the jog button is operated, another contact thereon connects thewire 184 to a wire 189 and this substitutes for the stop timing switch64. Hence, while the jog button is held depressed, the pallet-advancingmechanism operates in the same manner as it did under automaticoperation but for one cycle only because the relay 149 will prevent arepeated pallet-advancing cycle the same as it would if the switch 145were in automatic position.

According to the present invention, provision is made for operating thetool units T under the control of the jog button 187 along with thepallet-advancing means or operating the pallet-advancing means alone.When it is desired to operate the pallet-advancing means but not thetool unit T, a switch 190 in the line 158 is opened before the jogbutton 187 is operated.

When it is desired to advance the pallets in the rows a in smallincrements of movement under manual control, inching mechanism providedby the present invention may be employed. The inching mechanism shownincludes a manually operable spring-returned push button switch 191having a contact 191a which is connected to the feed line 121 by a wire192 and is connected to the series of feed-rod return switches 67, 66aand 68a between the switches 6-7 and 65a to shunt out the latter.

In addition, the inching switch 191 has another contact 19112 which isconnected by a wire 193 to an inching valve coil 194, and the other sideof the contact 1911) is connected by a wire 195 to a switch '196operated by the relay 163 and current flows from the switch 196 thereofthrough a wire 197 which connects to the junction of switches 66a and68a which in turn are connected to the feed wire 121. If the feed lugs34 are not in palletengaging position, the switches 66a will be open andthe inching mechanism will be inoperative.

The coil 1% operates a spring-returned solenoid valve which bypasses thesolenoid valve 47 and supplies fluid to the pipe 48 of the cylinder 33which advances the pallets in the rows 15a.

Referring to the receptacle 104 shown in FIG. 16, a wire 198 isconnected to the feed line 120 to supply current for the sensingswitches on the tool units. Wires 199 are connected to a source of powerfor the tool units such as an electric motor continuously operating ahydraulic pump forming part of the tool units, and this current may besupplied either from the lines 1.16 or from a transformer fed by thelines 116. The wire 200 is used to ground the equipment.

The timing motor 60 as above stated is a variable speed motor and iscontrolled by a potentiometer 201. When the switches 114, 122 and havebeen closed and the machine is ready to operate, a lamp 202 connectedacross the relay .136 is energized. A lamp 203 connected across therelay 125 indicates when the hydraulic pump motor 127 is operating.

In order to permit the machine to be instantly stopped should anyaccident or malfunctioning occur, the present invention provides a cable204 which on suitable brackets 205 is stretched across both sides of themachine and directly above the ways '15. At one end of the machine thecables are anchored to the brackets 205 and at the other end of themachine the cables are connected to switches 1'31 and 132 respectively.The cable is maintained taut by springs 206. It will be remembered thatthe switches .131 and 132 are connected in series in the circuit leadingto the main relay 136, and therefore when either cable 204 is struck orleaned against, the safety switches 131 or 132 will be opened and themachine stopped.

The number and location of the sensing switches which are in series andare connected to the wire depend upon the particular tool units used andthe operations being performed. As representative of one arrangement,the sensing switches shown in FIG. 5 in connection with the verticaldrilling tool unit 'Dl, include a sensing switch 207 which is operatedby a rod 208 connected to a carriage 83. Also in FIG. 5 in connectionwith the horizontal tap unit 172, there is shown a sensing switch 209operated by a rod 210 operated by the carriage 2 11 of the unit.

Usually, the cable 106 connected to the attachment plug 105 extends to acontrol box 212 having means for individually controlling the tools ofeach tool unit. From the control box a cable 213 extends to a junctionbox 214 which terminates the wiring from the sensing switches andvarious other parts of the tooling.

It will be seen from the above that all that needs to be done to adaptthe machine to the present invention for any particular machining,assembling or other operation is to prepare appropriate work nests onthe pallets, select the needed self-powered tool units, mount them inposition along the track, plug them into one of the electricalreceptacles placed at convenient points along the machine, and finallyadjust the variable speed timing motor to select the desired timeinterval during which one complete cycle of operations should beperformed.

This is accomplished by the present invention by having permanentlybuilt into the machine the work-advancing means, including the automaticcontrols therefor, and the electrical system for automaticallyinitiating the operation of the tool units and for preventing faultyoperation by interrupting the operation of the machine should it fail tooperate as intended.

Instead of having the conduit 102 located in the channel 101 in the topplate 13 as shown in FIG. 5 for instance, it may be mounted on thesurface of the top plate or at considerable height above the top plate.

For instance, as shown in FIG. 18, the conduit 102a carrying the plugreceptacles 104 may be mounted on brackets 21-5 carried on the endsections 11 of the machine and extending substantially over the topplate 13. The conduit 102 may have a casing 216 carrying various signallamps. By having the conduit 10 2:: located well above the top 13, thedanger of short-circuiting, due to the presence of water and otherconductive fluids which may be used in the operation of the machine, isavoided.

It should be noted that, according to the present invention, by startingthe operation of tool units immediately upon the pallets in the rows 15areaching advanced position, the time required for one complete cycle ofthe machine is substantially shortened. This is because the advancementof the pallets in the rows 15a occurs almost instantaneously, theremaining operations of the palletadvancing mechanism taking place whilethe tool units are operating. The output of the machine per unit of timeis thus substantially increased.

In multi-operation machine tools as heretofore provided, when it wasdesired to change the length of time during which the machine completedone cycle, not only the working time was changed but also the timerequired for indexing, i.e., advancing the work.

According to the present invention, however, while the length of thecycling period of the machine may be varied by the single control asrepresented by the potentiometer 201, the change of speed of the timingmotor does not change the length of time during which the transfermechanism operates, since the transfer mechanism operates independently,although within the complete cycling time. The present inventiontherefore avoids the loss of time heretofore unavoidably involved by notunnecessarily lengthening the time within which the transfer mechanismoperates.

The term machining operations as herein used is intended to include alloperations which change the shape or form of a workpiece whether bycutting, swaging, grinding, spinning, or other similar operations.

The term assembling operation as herein used is intended to include alloperations in which several pieces are brought together to form anassembly, whether or not the pieces so brought together are joined asone.

In addition to being useful for machining, assembling and finishingoperations, the machine tool of the present invention may also be usedfor measuring or inspecting workpieces, and measuring tool units may, ofcourse, be used along with assembling, machining or finishing toolunits.

Variations and modifications may be made within the scope of the claimsand portions of the improvements may be used without others.

We claim:

1. A machine for supporting and moving a plurality of workpieces pastpotential work stations on opposite sides of the machine for sequenceoperations thereon, comprising a frame, a worktable supported on saidframe and having a horizontal rectangular tool-supporting surface whichis substantially planar and continuous and provided with an endlessmarginal gap therein, said marginal gap being rectangular and havingside portions and end portions adjacent to but spaced inwardly from andparallel with the sides and ends respectively of the worktable; aplurality of like rectangular work pallets arranged in said gap insideby-side relation forming spaced straight side rows and end rows eachrow having a plurality of pallets, said pallets overlying said gap andsubstantially filling the same to complete said work surface except forvoids at two diagonally opposite corners of the marginal gap, saidpallets in opposite side rows being slightly spaced to enable individualregistration thereof at said Work stations, and said pallets in said endrows being in abutting relation; tracks in the side portions and endportions of the gap to slidably support said pallets with their Worksurfaces in substantially the horizontal plane of said worktable; meansfor advancing the pallets simultaneously in both said side portions ofthe gap and located below each side row of pallets and comprisingreciprocating means :for individually engaging each pallet in each ofsaid side rows to advance each pallet in each side row simultaneouslyand intermittently a distance substantially equal to the width of eachpallet to a potential work station on the worktable whereby each palletin the side rows is selectively available for use to carry work and ispositively advanced in sequence from one potential work station on theworktable to a succeeding contiguous potential work station at eachoperation of the advancing means, reciprocating means for advancing thepallets of each of said end rows comprising reciprocating meanspositioned to engage only the last pallet to enter the end row and byedge-to-edge engagement of the pallets to advance all of the pallets ineach end ro-w en masse to position the leading pallet in the end row inthe void in the opposite side row and to present the opposite side ofeach pallet to the exterior of the table whereby opposite sides ofworkpieces supported on said pallet are made accessible from theopposite exterior side of the worktable; and means for alternatelyoperating the means for advancing the pallets in the side rows and themeans for advancing the pallets in the end rows, the portion of theworktable bounded by and adjacent each side portion of the endlessmarginal gap being suflicientiy extensive to provide a substantial worksurface whereby workpieces and tools may be supported thereby at saidwork stations.

2. A machine as set forth in claim 1 in which the means for advancingthe pal-lets in each side row of pallets comprises a longitudinallymovable and rotatable rod extending along the track beneath the row ofpallets and having a plurality of aligned lugs each lug being positionedto engage and disengage one pallet in the row, means for advancing andretracting each rod to advance each pallet from one work station on theworktable to the next when the rod is advanced, means responsive to thecompletion of the advancing movements of the rods for rotating the rodto disengage the lugs from the pallets, and means responsive to thereturn of the rod to starting position when retracted for causing therod to be rotated to cause the lugs to reengage the pallets and meansfor rendering the palletadvancing means inoperative upon failure of saidfeeding lugs properly to return to pallet-engaging positions.

References Qited by the Examiner UNITED STATES PATENTS 1,738,039 12/1929Cope 214l6.1 1,851,502 3/1932 Ferris 19885 X 2,201,939 5/1940 Auger2l4-16.l X 2,745,167 5/1956 Cross 2933 EVON C. BLUNK, Primary Examiner.

EDWARD A. SROKA, Examiner.

1. A MACHINE FOR SUPPORTING AND MOVING A PLURALITY OF WORKPIECES PASTPOTENTIAL WORK STATIONS ON OPPOSITE SIDES OF THE MACHINE FOR SEQUENCEOPERATIONS THEREON, COMPRISING A FRAME, A WORKTABLE SUPPORTED ON SAIDFRAME AND HAVING A HORIZONTAL RECTANGULAR TOOL-SUPPORTING SURFACE WHICHIS SUBSTANTIALLY PLANAR AND CONTINUOUS AND PROVIDED WITH AN ENDLESSMARGINAL GAP THEREIN, SAID MARGINAL GAP BEING RECTANGULAR AND HAVINGSIDE PORTIONS AND END PORTIONS ADJACENT TO BUT SPACED INWARDLY FROM ANDPARALLEL WITH THE SIDES AND ENDS RESPECTIVELY OF THE WORKTABLE; APLURALITY OF LIKE RECTANGULAR WORK PALLETS ARRANGED IN SAID GAP INSIDEBY-SIDE RELATION FORMING SPACED STRAIGHT SIDE ROWS AND END ROWS EACHROW HAVING A PLURALITY OF PALLETS, SAID PALLETS OVERLYING SAID GAP ANDSUBSTANTIALLY FILLING THE SAME TO COMPLETE SAID WORK SURFACE EXCEPT FORVOIDS AT TWO DIAGONALLY OPPOSITE CORNERS OF THE MARGINAL GAP, SAIDPALLETS IN OPPOSITE SIDE ROWS BEING SLIGHTLY SPACED TO ENABLE INDIVIDUALREGISTRATION THEREOF AT SAID WORK STATIONS, AND SAID PALLETS IN SAID ENDROWS BEING IN ABUTTING RELATION; TRACKS IN THE SIDE PORTIONS AND ENDPORTIONS OF THE GAP TO SLIDABLY SUPPORT SAID PALLETS WITH THEIR WORKSURFACES IN SUBSTANTIALLY THE HORIZONTAL PLANE OF SAID WORKTABLE; MEANSFOR ADVANCING THE PALLETS SIMULTANEOUSLY IN BOTH SAID SIDE PORTIONS OFTHE GAP AND LOCATED BELOW EACH SIDE ROW OF PALLETS AND COMPRISINGRECIPROCATING MEANS FOR INDIVIDUALLY ENGAGING EACH PALLET IN EACH OFSAID SIDE ROWS TO ADVANCE EACH PALLET IN EACH SIDE ROW SIMULTANEOUSLYAND INTERMITTENTLY A DISTANCE SUBSTANTIALLY EQUAL TO THE WIDTH OF EACHPALLET TO A POTENTIAL WORK STATION ON THE WORKTABLE WHEREBY EACH PALLETIN THE SIDE ROWS IS SELECTIVELY AVAILABLE FOR USE TO CARRY WORK AND ISPOSITIVELY ADVANCED IN SEQUENCE FROM ONE POTENTIAL WORK STATION ON THEWORKTABLE TO A SUCCEEDING CONTIGUOUS POTENTIAL WORK STATION AT EACHOPERATION OF THE ADVANCING MEANS, RECIPROCATING MEANS FOR ADVANCING THEPALLETS OF EACH OF SAID END ROWS COMPRISING RECIPROCATING MEANSPOSITIONED TO ENGAGE ONLY THE LAST PALLET TO ENTER THE END ROW AND BYEDGE-TO-EDGE ENGAGEMENT OF THE PALLETS TO ADVANCE ALL OF THE PALLETS INEACH END ROW EN MASSE TO POSITION THE LEADING PALLET IN THE END ROW INTHE VOID IN THE OPPOSITE SIDE ROW AND TO PRESENT THE OPPOSITE SIDE OFEACH PALLET TO THE EXTERIOR OF THE TABLE WHEREBY OPPOSITE SIDES OFWORKPIECES SUPPORTED ON SAID PALLET ARE MADE ACCESSIBLE FROM THEOPPOSITE EXTERIOR SIDE OF THE WORKTABLE; AND MEANS FOR ALTERNATELYOPERATING THE MEANS FOR ADVANCING THE PALLETS IN THE SIDE ROWS AND THEMEANS FOR ADVANCING THE PALLETS IN THE END ROWS, THE PORTION OF THEWORKTABLE BOUNDED BY AND ADJACENT EACH SIDE PORTION OF THE ENDLESSMARGINAL GAP BEING SUFFICIENTLY EXTENSIVE TO PROVIDE A SUBSTANTIAL WORKSURFACE WHEREBY WORKPIECES AND TOOLS MAY BE SUPPORTED THEREBY AT SAIDWORK STATIONS.